The equine immune system is a complex network of cells, tissues, and organs that work collaboratively to defend against pathogens and maintain homeostasis. It consists of innate and adaptive components, each with distinct functions and mechanisms. The innate immune system provides the first line of defense through physical barriers, phagocytic cells, and the complement system. The adaptive immune system involves lymphocytes, such as B cells and T cells, which generate specific responses to antigens and provide immunological memory. Research in equine immunology explores the interactions between these components, the impact of genetic and environmental factors on immune function, and the development of vaccines and therapeutics. This page gathers peer-reviewed studies and scholarly articles focusing on the mechanisms, regulation, and clinical applications of the equine immune system in health and disease.
Olitsky PK, Harford CG.Young (12 to 15 day old) mice are approximately as susceptible to the virus of equine encephalomyelitis, Eastern or Western strain, when it is given intraperitoneally as are adult mice when the virus is injected intracerebrally. With this susceptibility by the intraperitoneal route as a basis, the injection of immune serum-virus mixtures intraperitoneally was found to result in protection in dilutions which give rise to infection after intracerebral inoculation. The difference of protective power by the two indicated routes was shown not to depend on the amount of inoculum nor on the age of th...
Olitsky PK, Cox HR, Syverton JT.We have studied certain properties, additional to those previously described (3), of the virus of vesicular stomatitis of horses, and of the characteristic biological reactions of the virus of equine encephalomyelitis. It has been found that the virus of stomatitis, ordinarily dermotropic, can acquire neurotropism and the neurotropic encephalomyelitis virus can, in turn, be rendered dermotropic in its action. The neurotropism in both instances is associated with definite, although not pronounced, viscerotropism. Both viruses can bring about a similar infection in the white mouse, rat, guinea p...
Parker JT, McCoy MV.1. The serum of horses immunized with increasing doses of certain anaerobically produced autolysates of pneumococci contain potent neutralizing antibodies for the pneumotoxin. 2. The method for the in vitro titration of these horse antipneumotoxic serums is given.
Friedlander M, Sobotka H, Banzhaf EJ.The precipitin indices for a number of monovalent and polyvalent antipneumococcus sera were determined under known conditions, and found to vary as did the number of protective units. The ratio precipitin index/protective units in monovalent sera was found to lie between 2.8 and 4.8 for Type I and to be about ten times greater for Type III. Lower values were found in polyvalent horses and when mixing heterologous monovalent sera with each other. The influence of the duration of treatment upon the quotient was studied. Several refined and concentrated preparations showed a relative increase in ...
Wadsworth AB, Sickles GM.IT HAS BEEN SHOWN THAT THE PNEUMOCOCCUS MULTIPLYING IN THE TISSUES OF THE IMMUNIZED ANIMAL (HORSE) BECOMES ATTENUATED: loses, in varying degrees, its virulence, capacity of capsule formation, susceptibility to phagocytosis, and type specificity. The antigenic activity as an immunizing agent and the production of "soluble specific substance" are also altered. In some instances, the typical pneumococcus characteristics may be quickly restored by one or two passages through a susceptible animal (mouse). In others, virulence is not recovered and the organism remains atypical. Whether these changes...
Reimann HA.It is conceivable that a change from the virulent, non-phagocytable S form of Pneumococcus to the avirulent phagocytable R form may take place in pneumococcus disease, but the experiments here reported do not settle the question whether or not this is an important factor in determining the outcome in natural infection. It has been shown experimentally that the degradation from the S form to the R form actually does take place in cultures of Pneumococcus growing in agar subcutaneously embedded in guinea pigs, in agar enclosed in vials subcutaneously embedded in rabbits, and spontaneously in the...
Jungeblut CW.1. A flocculation reaction has been described which occurs between alcoholic extracts of pneumococci and antipneumococcus serum. 2. The reaction appears to be species-specific. It is not strictly type-specific, as slight or moderate cross-reactions occurred between Type I serums and Type II and Type III extracts. 3. The flocculating power of the serum from five horses undergoing immunization with pneumococcus, Type I, did not develop to any extent before the end of the 4th or 5th month. 4. In the case of two of these horses in which it was possible to carry out parallel tests on a larger numbe...
Cain JL, Norris JK, Swan MP, Nielsen MK.The microbiome plays an important role in health, where changes in microbiota composition can have significant downstream effects within the host, and host-microbiota relationships can be exploited to affect health outcomes. Parasitic helminths affect animals globally, but an exploration of their microbiota has been limited, despite the development of anti-Wolbachia drugs to help control infections with some filarial nematodes. The equine ascarids, Parascaris spp., are considered the most pathogenic nematodes affecting juvenile horses and are also the only ascarid parasite to have developed wi...
Tinarwo M, Dennis SJ, Hitzeroth II, Meyers AE, Rybicki EP, Mbewana S.African horse sickness (AHS) is a severe, noncontagious disease of equines caused by the African horse sickness virus (AHSV). The virus has nine serotypes and is transmitted by the midge. AHS is endemic in South Africa and other sub-Saharan African countries. Currently, the disease is managed using a live attenuated vaccine manufactured by Onderstepoort Biological Products (OBP). Although this vaccine has been in use for decades, it has several drawbacks, including the possibility of reversion to virulence, and it does not allow for the differentiation of infected horses from vaccinated horse...
Al-Rammahi HM, Mohsen RK, Othman RM.West Nile virus (WNV) circulates between birds and mosquitoes, with horses and humans as incidental dead-end hosts. Despite documented cases in neighboring countries and human cases in southern Iraq, no previous studies have investigated WNV in Iraqi horses. Unassigned: To determine the seroprevalence of WNV in horses from three southern Iraqi governorates (Thi-Qar, Misan, and Basrah) between March and June 2024. Unassigned: Blood samples were collected from 236 horses regardless of age, sex, or health status. Serum samples were analyzed using commercial competitive enzyme-linked immunosorbent...
Souto PC, Santos MR, Orozco AMO, Bento LD, Ramirez-Lopez CJ, Girardi FM, Machado JCA, de Oliveira LL, da Fonseca LA.We aimed to develop a species-specific ELISA for qualitatively and quantitatively determining serum amyloid A (SAA) in horses. Current methods for measuring SAA in horses utilize ELISA or immunoturbidimetric tests designed for human SAA, which are not specific to horses. Mice and rabbits were used to generate polyclonal antibodies against equine SAA. The study examined serum samples from 32 horses with acute inflammatory disease (SG) and 25 clinically healthy horses. Furthermore, the SAAeq kinetics were observed in three horses from the SG group at three different timepoints. The SAA-ELISA est...
Domínguez-Odio A, González LIC, Alfonso DM, Guevara-Hernández F, La O Arias MA, Zayas MP, Ríos MÁB.The transmembrane glycoprotein gp45 (implicated in virus-equine B lymphocyte binding and in subsequent infection) is an important protein used as an antigen in the serological diagnosis of equine infectious anemia, but synthetic peptides derived from its structure are not. Consequently, the present study aimed to determine the diagnostic performance of the Bio-AIELAB immunoassay (novel synthetic peptide P05/gp45) in comparison with a similar commercial assay (ELISA EIA, VMRD Inc, USA) and with the gold standard (AGID, LABIOFAM, Cuba). A total of 365 samples of sera from naturally infected Cuba...
Houben RMAC, van Maanen C, Newton JR, van den Broek J, Sloet van Oldruitenborgh-Oosterbaan MM, Heesterbeek JAP.Equine herpesvirus 1 (EHV-1) infection is the cause of high impact disease syndromes, affecting the global horse industry. The effect of vaccination on transmission dynamics of EHV-1 in naturally occurring outbreaks is not quantified. Our aims were to estimate R for EHV-1 in equine populations from outbreak data, and evaluate the effect of vaccination status of the herd on R through a systematic review, model-based estimations and meta-analysis. A literature search for outbreak reports was carried out. Depending on available data, the early epidemic growth rate (GR) or final attack rate (AR) a...
Abreu MC, Conrad NL, Gonçalves VS, Leite FPL.Probiotic microorganisms can stimulate an immune response and increase the efficiency of vaccines. For example, Bacillus toyonensis is a nonpathogenic, Gram-positive bacterium that has been used as a probiotic in animal supplementation. It induces immunomodulatory effects and increases the vaccine response in several species. This study aimed to evaluate the effect of B. toyonensis supplementation on the modulation of the immune response in horses vaccinated with recombinant Clostridium tetani toxin. Twenty horses were vaccinated twice, with an interval of 21 days between doses, and equally di...
Soliman R, Yousef M, Gelil SA, Aboul-Ella H.Strangles is a highly contagious disease of the equine upper respiratory tract caused by Streptococcus equi subspecies. Streptococcus equi subsp. equi (S. equi) and Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) was isolated, as local, hot, and field strains, from horses clinically suffering from respiratory distress. The isolated Streptococci were identified using bacteriological and molecular techniques. Four formulations of inactivated S. equi vaccines were developed and evaluated. The first formulation was prepared using the S. equi isolates, adjuvanted with MONTANIDE GEL adjuv...
Atwa AS, Gomaa L, Elmenofy W, Amer HM, Ahmed BM.Equine influenza (EI) is a transmissible viral respiratory sickness of the family. Two viruses, H7N7 and H3N8 caused EI; however, H7N7 has not been detected for decades. H3N8 has circulated and bifurcated into Eurasian and American lineages. The latter subsequently diversified into Kentucky, South America, and Florida sub-lineages. Florida clade 1 (FC1) and Florida clade 2 (FC2) strains are the only circulating EI viruses (EIVs) in the meantime. Immunization is considered the major means for the prevention and control of EI infection. Using disparate technologies and platforms, several vaccin...
Hassanien RT, Thieulent CJ, Carossino M, Li G, Balasuriya UBR.(1) Background: equid alphaherpesvirus-1 (EHV-1) is a highly contagious viral pathogen prevalent in most horse populations worldwide. Genome-editing technologies such as CRISPR/Cas9 have become powerful tools for precise RNA-guided genome modifications; (2) Methods: we designed single guide RNAs (sgRNA) to target three essential (ORF30, ORF31, and ORF7) and one non-essential (ORF74) EHV-1 genes and determine their effect on viral replication dynamics ; (3) Results: we demonstrated that sgRNAs targeting essential lytic genes reduced EHV-1 replication, whereas those targeting ORF74 had a negligi...
Dahlgren AR, Careddu F, Norris JW, Adili R, Kropp EM, Li Q, Holinstat M, Biunno I, Balduini A, Tablin F, Shavit JA, Finno CJ.SEL1L is a well-known protein in the endoplasmic reticulum associated degradation (ERAD) pathway. While it is known to be expressed in platelets, SEL1L has never been shown to play an active role. Here we find evidence that SEL1L regulates platelet function. We first identified SEL1L through the study of Atypical Equine Thrombasthenia (AET), an autosomal recessive platelet disorder found in Thoroughbred horses. A missense variant in (c.1810A>G p.Ile604Val) was found in AET-affected horses, which we show is associated with decreased protein expression. SEL1L is intracellular in equine platelet...
Varela V, Costa M, Maciel C, Barbeito J, Barrera EE, Gutierre E, Correa A, Elgue M, Carrasco S, Larrosa MD, Pereira M, Correa J, Crosignani N....Anti-NGF monoclonal antibodies have recently been approved for treating degenerative joint disease, including osteoarthritis pain, in dogs and cats. However, their widespread use is limited by high cost and the requirement for repeated injections. Nerve Growth Factor and Substance P play central roles in the initiation and maintenance of inflammation and chronic pain in OA. There is a pressing need for new, safe, cost-effective therapies that target the underlying mechanisms of OA chronic pain. Here, we designed and produced a novel recombinant fusion protein, termed rNGFSP, which functions as...
Ribeiro MG, Barbosa AN, Pereira JG, Possebon FS, Pinto JPAN, Portilho FVR, Bello TS, Paz PJL, Arabe Filho MF, Panegossi LC, Reznik AU, Zeferino LO....Rhodococcus equi, a versatile and adapted opportunistic in nature bacterium, infects animals and humans. This soil-borne microorganism widely occurs in farms. Its dissemination occurs by feces from domestic animals (particularly horses, cattle, and pigs). In the last decades, bacterial virulence has been strongly attributed to plasmid-encoded virulence-associated proteins (VAPs). To date, three virulence plasmid types have been recognized: pVAPA, pVAPB, and pVAPN, which are considered host- or livestock-adapted. The pVAPA type is related to equine isolates (horse-type), the pVAPB type is assoc...
Kern-Allely C, Scott D, Magzamen S, Duncan C.Air pollution is a major global health threat that is expected to worsen, yet its effects on domestic animals remain poorly understood. The objective of this scoping review was to synthesize existing evidence on associations between ambient air pollutants and health outcomes in domestic animals and to identify gaps to guide future research. Unassigned: A scoping review was conducted following the Arksey and O'Malley framework and Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews guidelines with 2 search databases (PubMed and Web of Science) using ...
Prasad S, Patel B, Kumar P, Lall R.Postbiotics, which are preparations of inanimate microorganisms and their components, have emerged as a promising functional ingredient in animal health and nutrition. Postbiotics are primarily composed of microbial cell fractions, metabolites, enzymes, vitamins, polysaccharides, and short-chain fatty acids. Unlike probiotics, postbiotics do not contain live microorganisms, which strengthens their greater stability and safety in feed/food formulations. Postbiotics offer several beneficial effects, including antioxidant, anti-inflammatory, immune-modulatory, and antimicrobial actions. They enha...
Yerlikaya Z, Miranda-CasoLuengo R, Jahns H, Byrne O, Meijer WG, Mulcahy G, Walshe N.Cyathostomins are the most prevalent and currently considered the most pathogenic gastrointestinal nematodes in horses. Their life cycle includes an encystment phase within the large intestinal mucosa, where up to 90 % of the total worm burden resides. Clinical disease ranges from chronic protein-losing enteropathy to acute, sometimes fatal, typhlocolitis. Despite their significance, the ecological interplay between cyathostomins, the host immune response, and the gut microbiota remains poorly understood. To our knowledge, this is the first study to investigate these interactions at the mucos...
Iwasaki N, Llewellyn J, Brown J, Zamboulis DE, Finding EJT, Wheeler-Jones CPD, Thorpe CT.Tendon degeneration is common, and its risk increases with age both in humans and horses. Tendon regeneration and healing is limited due to inherent low cell density and vascularisation, and current treatments are insufficient as indicated by scar tissue formation and a high re-injury rate. The tendon vasculature plays a crucial role in tendon homeostasis, regeneration and healing, making it a potential therapeutic target. However, the effect of ageing on the tendon microvasculature is poorly understood. Here, we provide the first comprehensive characterisation of the tendon microvasculature. ...
Verstraete MH, Kuijpers F, Holl W, Norris J, van Heule M, Martin-Pelaez S, Heard C, Uribe-Salazar J, Armien A, Conley A, De Spiegelaere W....The endometrium is a hormonally responsive tissue that undergoes cyclic remodeling. Although endometrial organoids have been established in several species, detailed characterization remains limited. Here, we assessed the structural and molecular fidelity of equine endometrial organoids across reproductive cycle stages and during extended culture. Organoids were generated from biopsies collected during estrus and diestrus and analyzed using histology, immunohistochemistry, electron microscopy, and bulk- and single-cell RNA sequencing. Organoids formed polarized cystic structures composed of co...
Vollmuth Y, Jungbäck N, Grochowski P, Mögele T, Stark L, Zarrabi NS, Schlegel J, Schaller T, Märkl B, Matiasek K, Liesche-Starnecker F.Borna disease virus 1 (BoDV-1) has long been recognized as a cause of fatal encephalitis in animals and was only recently identified as a zoonotic pathogen causing a similar disease in humans. This study provides the first comprehensive comparative analysis of BoDV-1-induced neuropathology in human and animal end hosts, including horses, sheep, and alpacas. Using immunohistochemical analyses, we investigated the topographical distribution of BoDV-1 and inflammatory responses in the central nervous system across 19 cases. Key findings reveal distinct differences and overlaps between humans and ...
Zhang Y, Guo X, Yu M, Sun L, Qu Y, Guo K, Hu Z, Liu D, Zhang H, Wang X.Host ANP32 family proteins are crucial for maintaining the activity of influenza RNA polymerase and play an important role in the cross-species transmission of influenza viruses. To date, the molecular properties of equine ANP32 (eqANP32) protein are poorly understood, particularly the mechanisms that affect equine influenza virus (EIV) RNA polymerase activity. Here, we found that there are six alternative splicing variants of equine ANP32A (eqANP32A) with different levels of expression. Further studies showed that these six splicing variants of eqANP32A supported the activity of EIV RNA polym...
Błaszczak A, Olczak K, Stefaniuk-Szmukier M, Tomczyk-Wrona I, Musiał AD, Grzegorczyk J, Długosz B, Szmatoła T, Ropka-Molik K.Insect bite hypersensitivity (IBH) is a prevalent allergic skin disease in horses that significantly affects animal welfare and shows evidence of genetic predisposition. Objective: Understanding the genetic basis of IBH can improve management and breeding strategies. The Equine80K BeadChip microarray was used to identify genomic regions associated with the occurrence of IBH in Hucul horses. Methods: Hair samples were collected from 127 Hucul horses, including both affected individuals and controls. DNA was extracted and genotyped. A genome-wide association study (GWAS) was performed to identif...
Boozarjomehri Amnieh S, Ropka-Molik K.The horse is a distinctive translational model for bridging mechanistic discovery and clinically relevant investigation because of its physiological complexity, long lifespan, athletic phenotype, and broad spectrum of naturally occurring conditions that parallel aspects of human health and disease. Its utility extends from musculoskeletal and joint research to immunology, metabolic disorders, and exercise physiology, particularly where naturally developed disease, clinically applicable imaging, and longitudinal sampling are required. Additionally, it offers opportunities to examine both chroni...
O'Brien K, Mair T, Mudhar HS, Pesavento P, Miller H, Priestnall SL, Suárez-Bonnet A.Equine squamous cell carcinomas (eSCCs) are common, and a proportion are likely induced by papillomavirus 2 (EcPV-2). Accurate prediction of clinical outcomes is challenging with no recognized prognostic criteria or consistent histopathological classification scheme for eSCC. The aims of this study were to histopathologically subtype a large case series of eSCCs (genital and ocular) and correlate them with p16 and HER-2 expression, equine papillomavirus infection status, and various clinical and histopathological parameters to predict tumour behavior and prognosis. One hundred and eighty-five...
An T, Dugarjaviin M.(1) Background: The "Bider marking" on the shoulder of the Dun Mongolian horse represents a unique pigmentation pattern, the molecular formation mechanism of which remains incompletely understood. This study investigates the differential expression and protein localization of pigment-related genes-specifically the core transcription factor , as well as , , and -in the skin. The analysis focuses on three distinct regions: the dark-colored area of the 'Bider marking' shoulder (BIDC), the light-colored area of the 'Bider marking' shoulder (BILC), and the non-Bider-marked shoulder area (NBIS). The...
Elsawy BSM, Alzan HF., a recently discovered tick-borne hemoparasite infecting equids globally, has significant implications for equine health. Although it is closely related to (sharing 23% genomic divergence), it establishes an asymptomatic carrier state in persistently infected horses, creating a silent transmission reservoir. Its discovery and unique genetics justify its classification as a new taxon. A critical diagnostic challenge is that the lack of the gene in prevents its detection by the standard cELISA, emphasizing the need for species-specific tools. Although species-specific PCR assays, including ...
Kapadia CL, Crook RA, Coleman S, Unger G, Douglas RH, Fedorka CE.Altrenogest is commonly used in equine veterinary medicine for the control of estrus, behavioral modifications, and maintenance of pregnancy. Recent studies have found that altrenogest may impact aspects of the immune system, including altering cytokine production in circulation and within the reproductive tract. Therefore, we hypothesize that this alteration may lead to a deviated immune response to vaccination. Sixteen mares were divided into two groups, with ten mares (n = 10) receiving long-acting injectable altrenogest (100 mg/mL; IM) administered every 10 days, and six mares (n =...
Sjolin E, Zakia LS, Galezowski A, Whitehead AE.Literature on the seroprevalence of antibodies to the causative agents of equine protozoal myeloencephalitis (EPM) in Canada is limited. Objective: To determine the prevalence of serum antibodies against Sarcocystis neurona and Neospora hughesi in apparently healthy horses without signs of neurologic disease which have always resided in Alberta, Canada, using commercially available immunodiagnostic tests. Methods: Samples from 116 healthy horses were obtained from a biobank containing horse serum collected across Alberta in 2021 and 2022. Samples were selected based on owner survey responses, ...
Bruneel E, Hermange T, Casamatta JM, Pereira A, Pimenta J, Caseiro AR.Immune-mediated keratitis (IMMK) is a chronic inflammatory corneal disease in horses. Long-term topical therapy with cyclosporine is often impractical, highlighting the need for sustained-release alternatives. Objective: To assess clinical response, tolerability, and duration of effect of episcleral silicone matrix cyclosporine implants (ESMC) in horses with presumed IMMK. Methods: Medical records of 12 horses (14 eyes) treated between 2019 and 2023 were retrospectively reviewed. IMMK subtypes were classified as epithelial (n = 3 eyes), anterior stromal (n = 9), or mid-stromal (n =...
Liang S, Xu Z, Liu X, Yang Y, Zhao L, Hu C, Hou J, Wei Z, Zhang Y, Li D, Yang J, Zhang J, Bi J, Wang Y, Lou Z.Western equine encephalitis virus (WEEV), a group of encephalitic alphaviruses that cause severe diseases in humans and equids, historically used the very-low-density lipoprotein receptor (VLDLR) as a receptor during infection. However, current epidemic strains no longer use VLDLR as a receptor. In this study, we identify that LA1, LA2, LA3, and LA5 of VLDLR can directly interact with WEEV. Using cryo-electron microscopy, we investigate the structures of complexes formed between WEEV and VLDLR-LBD or other VLDLR fragments. Our findings show that LA1 and LA2 insert into a cleft formed by two ad...
